Vintagesewing.info hosts considerable amount of free resources and material for anyone who is interested in vintage sewing. Whole books are online You can browse the site by decade or category. Key categories being Dressmaking & Sewing, School Textbooks, Sewing Courses, Pattern Design, Tailoring and Accessories.
There are some real gems to be discovered on this site. For instance in the section on Accessories there are directions (written in the 1950’s) on glove making and information on hats published in 1922. Much of the information in this type of material is of interest to historical costumers and many of the garment construction techniques are still used today.
For sheer charm however I think the pick of the crop is the 1893 edition of Olive C. Hapgood’s “School Needlework, A Course of Study in Sewing designed for use in Schools” which opens with
DEAR GIRLS: You have now become old enough to prepare for woman’s duties; one of these is the art of sewing, which we will take up as simply as possible. By following the given directions carefully, you will become able to dress your dolls, assist your mothers in mending, make garments, fancy articles, etc.